panfrost: Fix a warning

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <!7040>
37 jobs for !7040 with panfrost-misc-fixes in 9 minutes and 21 seconds (queued for 4 seconds)
merge request